A system for heart performance characterization and abnormality detection includes an interface for receiving signal data representing an electrical signal indicating electrical activity of a patient heart over multiple heart beat cycles. A signal processor uses the received signal data in calculating at least one of, (a) a first signal characteristic value substantially comprising a ratio of a time interval from S wave to T wave, to a time interval from Q wave to S wave and (b) a second signal characteristic value substantially comprising a ratio of a T wave base voltage from a peak of a T wave to a zero base reference voltage, to an R wave base voltage from a peak of an R wave to a zero base reference voltage. A comparator compares at least one of the first and second characteristic values with a threshold value to provide a comparison indicator. A patient monitor in response to the comparison indicator indicating a calculated signal characteristic value exceeds the threshold value, generates an alert message associated with the threshold.